中文摘要：

【目的】通过研究小麦体内过氧化物酶、多酚氧化酶、苯丙氨酸解胺酶活性的变化规律与植原体侵染过程及品种抗病性的关系，从生理生化学角度揭示小麦品种抗蓝矮病的机制，为蓝矮病的防治和生产上选育优质小麦抗病品种提供理论依据。【方法】对抗、感小麦品种（烟D27、小偃6号）接种小麦蓝矮病植原体，观察其症状变化，同时采用紫外分光光度计法，定期测定小麦叶片的过氧化物酶（POD）、多酚氧化酶（PPO）及苯丙氨酸解胺酶（PAL）活性并进行比较分析。【结果】症状观察发现，感病品种的潜育期为12d左右，抗病品种为18d左右。防御酶活性的测定表明，随着植原体的侵染，抗病品种的3种防御酶活性均有不同程度的提高，活性提高幅度较大的时期因酶而异，但早于感病品种；感病品种防御酶活性升高较慢且较抗病品种滞后，有时甚至出现酶活性下降现象。【结论】小麦蓝矮病潜育期长短因品种抗性而异，3种防御酶活性变化规律不仅与品种抗性有一定的相关性，而且与植株发病程度密切相关，这些防御酶活性出现的峰值高低与早晚，可作为小麦抗蓝矮病早期鉴定的一种有价值的重要生理指标。

英文摘要：

[Objective] The relation between the changes in activities of three defendant enzymes peroxidase（POD）,polyphemol oxidase（PPO）and phenylalanine ammonia lyase （PAL） in different wheat cultivars infected by wheat blue dwarf phytoplasma（WBD） and resistance to phytoplasmas were studied to investigate its resistant mechanism and provide theoretical basis for controlling the disease and selecting resistant varieties. [Method] The activities of POD,PPO and PAL in one resistant and one susceptible wheat cultivars infected by WBD were measured using spectrophotometer. [Result] The results showed that the incubation period of resistant cultivar was 12 days and susceptible 18 days and the enzyme activities of PPO,POD,PAL in resistant cultivar markedly increased with the increase of the time course of infection and the disease expansion, the peak of their activities appeared earlier than in susceptible one. [Conclusion] These results suggested that early rapid increase of three enzyme activities might be used to serve as one of the valuable physiological indices for the selection of wheat resistant cultivar to WBD.